IOL: biometry: practice question

A Ophthalmology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Ophthalmology · IOL: biometry

Sample item

Which measurements are needed to calculate IOL power before cataract surgery?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Axial length and keratometry

Formulae such as SRK II or SRK/T use axial length from A-scan or optical biometry, keratometry and an A constant. Errors in axial length are the main cause of postoperative refractive surprise.

Option by option

  • A. Intraocular pressure and pachymetry

    IOP and pachymetry are for glaucoma.

  • B. Axial length and keratometry (correct)

    Correct. Axial length and K readings feed the IOL formula.

  • C. Visual field and colour vision

    Fields and colour vision are neuro-ophthalmic tests.

  • D. Schirmer test and break-up time

    Tear tests assess dry eye.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is B, Axial length and keratometry. Formulae such as SRK II or SRK/T use axial length from A-scan or optical biometry, keratometry and an A constant.

Why is "Intraocular pressure and pachymetry" not the answer?

IOP and pachymetry are for glaucoma.

Why is "Visual field and colour vision" not the answer?

Fields and colour vision are neuro-ophthalmic tests.

Why is "Schirmer test and break-up time" not the answer?

Tear tests assess dry eye.

What concept does this question test?

It tests IOL: biometry in Ophthalmology. Errors in axial length are the main cause of postoperative refractive surprise.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study IOL: biometry?

Group the red eye by what to examine and what the pupil does. Then use the flashcards and the other Ophthalmology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.